A $1bn (£636m) lawsuit has been launched against a businessman known as the King of Diamonds.
Lev Lieviev, an Uzbekistan-born Israeli millionaire, is being sued by Russian business rival Arkady Gaydamak at the High Court over a major diamond export operation.
Gaydamak, 59, who lives in Israel, claims he was due commission of approximately $3m a month from a company set up in 2000 to export diamonds from Angloa while the country was embroiled in civil War.
Gaydamak, the father of former Portsmouth FC owner Sacha Gaydamak, claims he has received nothing since 2004.
Leviev, 55, was given the industry nickname of King of Diamonds after having spent 40 years in the trade. He lives in Hampstead in a £35m property.
He argues that Gaydamak made a deal with the Angolan government that signed away his rights to further dividends.
The case will see chief rabbi of Russia, Berel Lazar, called as a witness. Gaydamak claims that he was given a copy of the contract. An Angolan army chief will also be called.
Gaydamak watched the day's court proceedings via a video link, as he is subject to a European arrest warrant over tax affairs.